Strap guide track



May 1, 1962 J. F. DANIELS ETAL 3,031,949

STRAP GUIDE TRACK Filed Aug. 24, 1959 4 Sheets-Sheet 1 21 nun INVENTQRS 2 1 JGUn. F. Damds Rolwa-I mam Q Paw;

May 1, 1962 J. F. DANIELS ETAL STRAP GUIDE TRACK 4 Sheets-Sheet 2 Filed Aug. 24, 1959 o @m @m M 5 mm mm 3 2w Pm) o o, Q 6 qv wmm mm mm J NQ @q mm ma nw NWI U80 Mm WW J [\1 MW 4A a 1 m a 3w w o mm W r MR r) w. W a @w m mm May 1, 1962 J. F. DANIELS ETAL STRAP GUIDE TRACK 4 Sheets-Sheet 3 Filed Aug. 24, 1959 United States Patent e 3,031,949 STRAP GUIDE TRACK John F. Daniels, Lisle, and Robert E. Hager, Park Forest, 11]., assignors to Acme Steel Company, Chicago, 111., a corporation of Illinois Filed Aug. 24, 1959, Ser. No. 835,664 7 Claims. (Cl. 100-26) This invention relates to improvements in box strapping apparatus and its purpose is to provide a novel device by which a binding strap is guided about a box or other object to be bound preliminary to drawing the strap taut around the object and then securing its ends together.

In the binding of boxes, packages and the like, it is common practice to encircle the box with a binding strap by a manual operation without the use of any guiding means. This method is rather slow and it is particularly unsatisfactory when large boxes or packages are being bound since it is then extremely difiicult for a single operator to cause the strap to form a loop encircling the package. In many binding operations, it has been necessary to use a second operator stationed behind the package to assist in directing the free end of the strap over the package to the first operator who has passed the strap rearwardly beneath the package. The problem is much the same whether the strap is finally drawn taut and its ends secured together by a manual operation or by the use of a power driven machine.

Guides have been provided by which the binding strap is guided about a package during the binding operation, both when the strap is fed manually or by a power driven machine. When the strap guide causes formation of a small enough strap loop, the springiness of the strap itself provides the means for retaining the strap in the guide without requiring special temporary strap retaining means until the loop is shrunk onto the package. However, when the strap guide is large and is used to form a large loop about the package, temporary strap retaining means is required in the guide to prevent the strap from falling away from the guide as the strap is fed around the guide.

different types of retaining means have been employed with varying degrees of success and objection.

One of the most significant objectionsis based upon the inability of the retaining means to gradually release the strap as the strap is withdrawn from the, guide and the strap loop is shrunk onto the package. Failure to gradually release results fromthe strap being hung up or snagged on the retaining means. This causes the band to be bent sharply at times which is objectionable in appearance on the package and, if the bent portion reaches the strap joint region, the bend can cause a faulty joint or none at all if it is bent enough.

It is an important object of this invention to provide an improved strap guide by which the strap is guided around a package during the binding operation which guide has improved means for releasably retaining the strap so that it can be gradually and progressively released from the guide without hanging up or becoming snagged on the guide portions, to thereby eliminate sharp bending of the strap upon strap withdrawal.

Another serious objection, particularly of the segmented or finger type guides, is thedifficulty often encountered during endwise feeding of the strap. Oftentimes the strap end presented to the guide is bent or bowed longitudinally. When presented to the ordinary finger or segmented type guides, the curved strap end is frequently directed by its curvature through one of the spaces between the segments or the fingers and thereby misdirected entirely out of the guide.

It is another object of this invention to provide an improved strap guide with improved strap retaining means to be formed ice which can receive and properly guide even strap having a leading end which is longitudinally bowed or curved when presented to the guide but which is straightened and held in a proper longitudinal shape by the strap retaining means as the strap is guided so that misdirection of the strap is eliminated.

Another difiiculty with some tracks is the problem of snagging of the strap end as the stray is fed endwise. Ex perience has shown that even though a strap guide is properly designed theoretically it may create snagging. The snagging has resulted from bent fingers or segments or burrs on them, and even though the deformation in the form of bends or burrs is only slight, snagging has still occurred, apparently because the strap ends are always cut sharply and have sharp corners which readily engage any protrusion.

It is therefore still another object of the invention to provide an improved strap guide having improved strap retaining means which eliminates snagging of the' leading end of the strap as it is guided into and fed around the strap guide.

These objects are accomplished by embodying closely wound springs in the side walls of the strap guide which temporarily retain the strap longitudinally curved properly against the bottom wall of the strap guide while the strap is guided and which springs are wound from round wire which progressively presents successive non-snagging round surfaces on successive convolutions of the springs to the strap end to eliminate the snagging problem pursuant to strap feed. The springs, being resilient, flex apart gradually and uniformly progressively as the strap is withdrawn from the guide when the strap loop is being shrunk onto the package. This eliminates the hanging up or snagging of the strap on portions of the strap retaining means to eliminate the objectionable sharp bending of the strap upon strap withdrawal.

Another difiiculty encountered with strap retaining means previously used is associated with a strap guide which is commonly known as a telescoping type used in baling operations. In such a type, a horizontal strap guide portion is raised or lowered while one end of it is guided in a vertical strap guide portion. The end guided in the vertical strap guide portion creates a wider than normal opening in the strap retaining means in the vertical portion which opening may extend for the entire length of a segment of a track which may be in the order of up to eight or nine inches. In such a situation, if the strap is curled or curved sufliciently longitudinally, when it reaches the vicinity of the wider than normal opening of the strap retaining means, it is free to be misdirected through the opening. By using the coil spring construction of this invention, a strap retaining means is provided which provides only a very short length wider than normal opening in the strap retaining means so that misdirection of the strap end through the opening is minimized.

Another advantage inherent in this invention is that it lends itself to the round corner construction of strap guides which usually presents some degree of difficulty. The reason for its advantage is that the coil springs can be easily bent around the corners and still operate properly to releasably retain the strap. In the past, oftentimes special corner sections of the strap track have been required.

Other objects and inventions should become apparent by referring to the accompanying drawings in which:

FIG. 1 shows a perspective view of a package or object which has been reinforced by a surrounding binding strap with the use of the apparatus of the present invention;

FIG. 2 shows an enlarged plan view of the welded joint 3 by which the ends of the binding strap ends shown in FIG. 1 are united;

FIG. 3 shows a somewhat diagrammatic vertical cross section taken through a machine embodying the present invention illustrating the means for guiding the strap when it is caused to encircle the package and illustrating the relative positions of the parts at the conclusion of the package encircling operation;

FIG. 4 shows a view similar to that of FIG. 3 at a later stage of the operation when the strap has been withdrawn from the guide means and contracted about the package;

FIG. 5 is a view similar to those of FIGS. 3 and 4 and illustrating the relative position of the parts when the package encircling portion of the strap has been severed from the supply end and a joint has been formed between the overlapping ends of that portion of the strap;

FIG. 6 shows an enlarged end elevation of a partial transverse vertical section through the upper portion of the machine which is illustrated diagrammatically in FIGS. 3, 4 and 5;

FIG.'7 is a partial end elevation similar to that of FIG. 6 showing a modified form of the present invention which is adapted to be used when the operation of extending the binding strap around the package is performed manually;

FIG. 8 shows a partial top plan view of the apparatus illustrated in FIG. 6;

FIG. 9 shows an enlarged vertical section taken on the line 99 of FIG. 6;

FIG. 10 shows a vertical section similar to that of FIG. 9 showing an alternate construction;

FIG. 11 shows a partial sectional view as viewed on the line 11-11 of FIG. 8; and

FIG. 12 shows a bottom view in partial section of the structure as shown in FIG. 11.

The apparatus of the present invention is adapted for use in guiding a metal strap around a box, package or other object which is to be reinforced and in FIG. 1 there is shown a perspective view of a box surrounded by a metal strap 21 which is drawn taut around the box and which has its overlapping ends joined together by means of spot welds 22 as shown particularly in FIG. 2. Other means for joining the ends of the strap may be employed if desired;

In FIGS. 3, 4, 5 and 6 of the drawings the invention is illustrated as being'embodied in a machine which is power operated for the purpose of feeding the strap around the box and drawing it taut. Referring to FIG. 6, it will be'seen that this invention comprises a table 23 upon which. there is mounted a track 24 having a substantially elliptical form and comprising a pair of parallel side plates 25 which are spaced apart and provided with openings 25a having a general rectangular form to receive the box 20. At the rear of the machine, the side plates 25 are provided at their lower extremities with outwardly extending horizontal flanges 25b which are secured to the top of the table 23 by screws 26 and, at the forward side of the machine, these side plates 25 are provided with other laterally extending horizontal flanges 25c which are secured to the table top by screws 27. The table top is provided with an opening 23a above which the box 20 is adapted to be mounted for binding purposes and, in this opening, there is mounted the mechanism by which the strap is fed through the track 24 and thereafter drawn taut, its supply portion cut 01?, and its ends joined by spot welding or the like.

As shown particularly in FIGS. 8 and 9 the side plates 25 of the track 24 are secured by studs 28 to a series of blocks 29 which are spaced apart about the track and which serve not only to connect the side plates 25 but also to support a channel 30 which is joined into a substantially elliptical form longitudinally to correspond to thegeneral contour of the track 24. This channel 34) is secured to the blocks 29 by a series of bolts or studs 31 and the channel serves as the supporting structure for the strap retaining means contained therein. The channel 3b is provided with an inner wall 3%, two side walls 3% and 300, and two spaced apart outer walls 36d and 30a. The channel 3tl is also secured to the side plates 25 by means of screws 28a.

The track 24 is adapted to extend completely around the position to be occupied by the box or object 20 and its extremities terminate in proximity to the margins of the openings 23a in the table over which the box 20 is adapted to belocated preliminary to the application of the binding strap.

Also secured by the screws 31.to the inner wall 3% of the channel 30 is a flat strip 30f which serves as the wall of the channel against which the strap 21 is ordinarily adapted to travel. On either side of this strip 39f is one of two coil springs 33 which are spaced from each other at their closest points a distance less than the width of the strap 21. These coil springs33 are of wound wire formed into closely wound circular convolutions 33a as viewed in FIGS. 6, 11 and 12. The diameters of these springs 33 are approximately equal to the spacing between the inside wall 30a and the outside walls 30d of the channel 30. Mounted between each of the side walls 30b and 30c and its adjacent coil spring 33 is a sponge rubber spacer strip 33b which is glued along its surface in contact with. one of the side walls 3% or 30c to hold it positioned. The two spacer strips 33b preferably extend continuously for the full length of the track 24 but neednot provided that they impart sub stantially continuous support for the coil springs for the entire length of. the track 24. Since the sponge rubber from which they are made is soft and resilient, the springs 33 can be transversely flexed against the strips 3312. when necessary.

The binding strap 21 is adapted to be drawnfrom asource of supply, not shown, by a power driven feed roll 35 and it is held in contact with that feed roll by an idler' roll 36. As the roll 35 rotates in the direction of the arrow 37, the strap 21 isprojected through the guide passage- 38a of the forward gripping dog 38 which is pivoted at 39 on the frame of the machine beneath the table. The strap then extends through a passage 40a (see FIG. 3) of a guide member 40 which is located beneath the middle portion of the box 20 and it then passes-above the rear gripping dog 41 and enters the guide channel of the guideway or track 24. As the rotation of the feed roll 35 continues, the strap 21 is pushed around the guideway 24 in contact with the inner face of the channel 30' until it emerges from the guide channel 24 and passes above the forward gripping dog 38 after which it enters a socket 40b, of the guide member 40, the movement of the strap being terminated by the engagement thereof with the end wallof this socket. The conditions are then substantially as shown in FIG. 3 with the binding strap 21 retained by the guide or track 24.

At this point, the forward gripping dog 38 is moved upwardly to grip the free end of the strap against a stationary gripping plate 42 so that this end of the strap is then held in stationary position. The feed wheel 35 is then reversed in its direction of rotation so that the loop of strap extending around the box 20 is contracted and the strap moves inwardly as permitted by the flexible coil springs 33. This movement continues until the strap is in close contact with the surfaces of the box 20. When all of the slack has been taken out of the loop of strap by the reverse operation of the feed roll 35, a pair of gripping dogs 43 are caused to grip the strap beneath the roll 35 and to be moved bodily downward to tighten the strap further until a predetermined condition of tautness has been brought about. When this condition is reached, the rear gripping dog 41 is moved upwardly about its pivot 44 until the supply portion of the strap is gripped against a stationary gripping plate 45. A pair of shearing blades 46 are then operated to sever the .5 supply portion of the strap adjacent to the inner end of the forward gripping dog 38, thus leaving the portion of the strap which encircles the box with two overlapping ends. 'Ihese ends are then secured together by the spot welds 22 which are efiected by the movement of an electrically actuated welding head 47 upwardly from the position ShOWn in FIG. 4, to the position shown in FIG. where it presses the overlapping strap ends against the welding points 48, thereby welding the strap ends together at the spaced points 22. When the welding operation has been completed the welding head 47 is retracted and the other parts are restored to their initial positions in readiness for a new binding operation.

The forward gripping dog 38 is adapted to be actuated by a link 50 having a coil spring 51 connected therein and having its lower extremity connected at 52 to a bell crank'lever 53. Similarly, the rear gripping dog 41 is actuated by a link 54 having a coil spring 55 connected therein and having its lower extremity connected at 56 to a bell crank lever 57. The feed roll 35 and the bell crank levers 53 and 57, as well as the welding head 47, are adapted to be actuated by a suitable mechanism, including rotary cams so that the successive movements of these parts take place in the proper timed relation as the binding of the box proceeds. A box strapping machine of this type is described and claimed in the Patent Number 2,882,814 of Alvin L. Winkler, Robert E. Hager and Kjell A. Falck-Pedersen, issued April 21, 1959.

Reference to FIGS. 11 and 12 indicates how the strap is removed from the strap retaining means when the loop of strap extending around the box is contracted. As the strap 21 is pulled in the opening 25a of the track 24, it is pulled from contact with the strip against the coil springs 33 to spread them apart in the immediate regions of contact. This spreading apart of the coil springs causes them to be flexed laterally into curved paths as indicated in FIG. 12 to allow for the passage of the strap 21 into the opening 2511. Since the coil springs 33 are backed by the resilient strips 3311, they quickly return to their straight shapes as the strap 21 is removed. Because of the resilient characteristics of the coil springs 33 and the resistance to flexing provided by the resilient strips 33b, the coil springs provide wider spacing in the regions where-the strap 21 progressively emerges from the track 24 along a very short length. The advantage of this is that this form of track can also be used efficiently in an apparatus where the track is of the telescoping variety with a horizontal track portion intersecting at one of its ends a vertical track portion with which it is movable vertically up and down. The fact that the unsupported length is so short when the coil springs are spread lends it well to that application since the opening required when transferring the leading strap end from the horizontal guide portion to the vertical guide portion is of only a short length and this more closely confines the strap and minimizes the possibility of it being misdirected out of the track. Also, since the coil springs 33 can be readily bent around corners and still operate as efliciently as in a straight track portion, this track construction lends itself to economy because no special corner track portions are required as in some other tracks.

While the apparatus of the present invention including the strap guiding channel or track may be employed with particular advantage in power operated machines, particularly those adapted for the binding of large boxes or the like, it may also be employed in binding operations which are carried on manually and, in FIG. 7, there is shown a modified form of apparatus which may be used for this purpose. As there shown, the machine comprises a guide channel 60 having side plates 61 which are secured to the table in the manner previously described and this guide channel extends forwardly over the position to be occupied by the box 62 to be bound. This guide channel terminates, however, short of the forward edge of the table so that it is possible to insert the box 62 from the forward side of the table and the strap 63 is thrust upwardly through the guide channel from a position beneath the box 62 until it emerges from the extremity 60a of the guide channel, whereupon this free extremity is seized by the operator and the strap is then pulled through the guide channel and passed around the box until the ends of the strap overlap. The strap may then be released manually from the springs 33 of the track and then drawn taut around the box by the use of the usual strap stretching tools. When the strap has been drawn taut its ends may be secured together by a strap sealing device or other means adapted to form an interlocking connection between the strap ends or other suitable form of joint. If desired, the complete annular guide shown in FIG. 6 could be used with a manual strapping operation.

In an alternative form the invention can be modified to the construction shown in FIG. 10. The side plates 25 support the blocks 29 in the same manner as before. But, the guide blocks 29 are secured to a flat strip 70 which is curved longitudinally to conform to the general shape of the track 24. A flat strip 30f is secured as before by means of the screws 31 and this strip serves as the wall of the track against which the strap 21 is ordinarily adapted to travel. Secured against the side plates 25 by means of screws 71 are two spring retainer strips 72 which extend longitudinally for the entire length of the track and are with the same longitudinal curvature as the strip 70 against which they are also positioned. These spring retaining strips 72 have recesses 73 which house coil springs 74 which are identical in shape to the springs 33 of the embodiment shown in FIG. 9. Proportionately they are shown smaller, but can just .as well be made as large or larger. In any case, their function is identical. Provided in the spring retaining strip 72 are recessed bores 75 which house coiled compression springs 76 which are positioned at close intervals around the entire track. These springs 76 serve .as resilient backing members for the other coil springs 74 in the same manner as the sponge rubber strips 33b do in the embodiment shown in FIG. 9.

Although the invention has been shown in only two different embodiments, it should be understood that the invention can be made in many difierent ways without departing from the true scope of the invention as defined by the appended claims.

We claim:

1. The combination in strapping apparatus of means for supporting an object, and a guide through which a strap may be fed endwise around the object, said guide having strap retaining means comprising resilient and flexible tubes extending longitudinally of the guide and spaced laterally of each other less than the width of the strap, and resilient means between the tubes and the side Walls of the guide to resist lateral flexing of the tubes.

2. The combination in strapping apparatus, of means for supporting an object, and a guide through which a strap may be fed endwise around the object, said guide having strap retaining means comprising coil springs extending longitudinally of the guide and spaced laterally of each other less than the width of the strap, and resilient means between the coil springs and the side walls of the guide to resist lateral flexing of the coil springs.

3. The combination in strapping apparatus, of means for supporting an object, and a guide for guiding a strap fed endwise around the object, said guide having strap retaining means comprising coil springs extending longitndinally of the guide and spaced laterally of each other less than the width of the strap.

4. The combination in strapping apparatus, of means for supporting an object, and a guide for guiding a strap fed endwise around the object, said guide having strap retaining means comprising resilient and flexible tubes 7 extending longitudinally of the guide and spaced laterally of each other less than the width of the strap.

5. The combination in strapping apparatus, of means for supporting an object, and a guide for guiding a strap fed endwise around the object, said guide having strap retaining means comprising coil springs closely wound of round Wire, said coil springs extending longitudinally of the guide and spaced laterally of each other less than the width of the strap.

6.v The combination in strapping apparatus, of means for supporting an object, and a guide having two opposite side walls between which a strap may be fed endwise around the object, said guide having strap retaining means comprising a resilient and flexible tube extending longitudinally of the guide along the vicinity of one side Wall of the guide and spaced laterally from the opposite side wall of said guide, and resilient means between the tube and 8 said onevsidewallt of thelguide to resist flexing of the tube.

7. The combination in strappingapparatus of means for supporting an object, and a guide through which a strap may be fed endwise around the object, said guide having strap retaining means comprising resilient and flexible tubes extending longitudinally of the guide and spaced laterally of each other less than the width ofthe strap, and resilient means between the tubes and the side Walls of the guide to resist lateral flexing of the tubes, said resilient means being a plurality of coil springs positioned to react between a guide portion and the tubes at right angles to thetubes.

References. Cited in the file of this. patent FOREIGNv PATENTS 804,226 Great Britain Nov. 12, 1958 

